Thin-film transistor liquid crystal displays (TFT-LCD) are a known variant of liquid crystal displays (LCD) which use thin-film transistor technology (TFT). These liquid crystal displays are used in many branches of industry and offer high image quality with good image contrast.
TFT-LCD's are also referred to as TFT modules and are used in display units in devices such as televisions, computer monitors, mobile telephones, hand-held video gaming systems, PDA's, navigation systems and projectors.
Display units including TFT modules are also used in the automobile industry as well, since they enable good readability of the displayed elements and a manipulation of the display, for example in the form of conventional digital display instruments or display instruments that are equipped with a cursor.
In addition, with TFT modules of suitable size, multiple display instruments may be provided in the display, along with additional information, such as route information in a navigation system.
In addition to the TFT module itself, such display units also comprise a backlighting unit, which is permanently connected to the TFT module. Since TFT-LCD's are non-luminous display elements, the backlighting unit ensures that light is projected from the back of the TFT module, that is to say, behind the TFT module from the point of view of the user, uniformly and over the entire surface of the LCD display, illuminating the display.
It is also customary to attach a joining layer and a front panel to the surface of the TFT module. To protect the display unit, a protective housing is used, which is connected to both the backlighting unit and the front panel.
Such a display unit is used in a vehicle, for example, and is thus exposed to a variety of strains, such as temperature changes, compressive and tensile stresses and vibrations.
Due to the rigid structure of the display unit, vibrations, for example, as well as compressive and tensile stresses which act on the protective housing also impact the front panel, the joining layer and the TFT module, and can thus lead to defects such as the Mura effect, or damage to the TFT module.